Question: When did Mika Waltari begin to go by Toimi?
Paraphrase: From which moment did Toimi be used by Mika Waltari?
SPARQL (Wikidata): SELECT ?value WHERE { wd:Q193111 p:P735 ?s . ?s ps:P735 wd:Q5395988 . ?s pq:P1545 ?value}